Describe primitive subsistence farming. How is this type of farming not eco-friendly?

Primitive subsistence farming, also known as slash-and-burn farming, involves clearing a forest patch by cutting and burning trees. The ash fertilizes the soil, and crops like rice, millets, yam, and cassava are grown using simple tools, without irrigation or fertilizers. Once soil fertility declines, the land is abandoned, and a new patch is cleared.

It is not eco-friendly as it leads to deforestation and loss of biodiversity.